Wavelength converter and semiconductor light emitting device

Abstract

According to an embodiment, a wavelength converter includes a resin allowing light emitted from a light source to pass through, a plurality of particle-shaped fluorescent substances dispersed in the resin, and fillers dispersed in the resin with a particle diameter smaller than the fluorescent substance. The fluorescent substances absorb the light emitted from the light source and emits fluorescence having a wavelength different from a wavelength of the light emitted from the light source; and a distribution of the fillers has higher density near the fluorescent substance than a density at a middle position between the fluorescent substances adjacent to each other.

What is claimed is: 
     
       1. A wavelength converter comprising:
 a resin allowing light emitted from a light source to pass through; 
 a plurality of particle-shaped fluorescent substances dispersed in the resin, the fluorescent substances absorbing the light emitted from the light source and emitting fluorescence having a wavelength different from a wavelength of the light emitted from the light source; and 
 fillers dispersed in the resin with a particle diameter smaller than the fluorescent substance, a distribution of the fillers having a density near the fluorescent substance that is higher than a density at a middle position between the fluorescent substances adjacent to each other. 
 
     
     
       2. The wavelength converter according to  claim 1 , wherein the density of the fillers in the resin increases closer to the fluorescent substance and decreases separating away from the fluorescent substance. 
     
     
       3. The wavelength converter according to  claim 1 , wherein the fillers are dispersed in the resin with a larger number than the number covering the whole surface of each fluorescent substance. 
     
     
       4. The wavelength converter according to  claim 3 , wherein the number of the fillers is 2×10 6  to 2×10 9  times the number covering the whole surface of each fluorescent substance. 
     
     
       5. The wavelength converter according to  claim 1 , wherein the fillers contain silica particles. 
     
     
       6. A semiconductor light emitting device comprising:
 a semiconductor layer having a first face, a second face disposed on a side opposite to the first face, and a light emitting layer, the semiconductor layer having a first region including the light emitting layer and a second region not including the light emitting layer; 
 a p-side electrode provided on the first region on the second face side; 
 an n-side electrode provided on the second region on the second face side; and 
 a fluorescent substance layer provided on the first face and including a transparent resin, a plurality of fluorescent substances dispersed in the transparent resin, and fillers dispersed in the transparent resin, a density of the fillers near the fluorescent substance being higher than a density of the fillers at a middle portion between the fluorescent substances adjacent to each other. 
 
     
     
       7. The device according to  claim 6 , wherein the density of the fillers in the resin increases closer to the fluorescent substance and decreases separating away from the fluorescent substance. 
     
     
       8. The device according to  claim 6 , wherein the filler allows the light emitted from the light source to pass through. 
     
     
       9. The device according to  claim 6 , wherein the fillers are dispersed in the resin with a larger number than the number covering the whole surface of each fluorescent substance. 
     
     
       10. The device according to  claim 6 , wherein the number of the fillers is 2×10 6  to 2×10 9  times the number covering the whole surface of each fluorescent substance. 
     
     
       11. The device according to  claim 6 , wherein the fillers contain silica particles. 
     
     
       12. The device according to  claim 6 , wherein concavo-convex is provided on the first face, and the fluorescent substance layer covers the concavo-convex. 
     
     
       13. The device according to  claim 12 , further comprising a second insulating film provided between the p-side interconnection and the n-side interconnection. 
     
     
       14. The device according to  claim 6 , further comprising:
 a first insulating film provided on a side of the second face, the first insulating film including a first opening communicating with the p-side electrode and a second opening communicating with the n-side electrode; 
 a p-side interconnection provided on the first insulating film and electrically connected to the p-side electrode through the first opening; and 
 an n-side interconnection provided on the first insulating film and electrically connected to the n-side electrode through the second opening. 
 
     
     
       15. The device according to  claim 14 , wherein
 the p-side interconnection includes a p-side interconnection layer provided both inside the first opening and on the first insulating film, and a p-side metal pillar provided on the p-side interconnection layer, the p-side metal pillar being thicker than the p-side interconnection layer; and 
 the n-side interconnection includes an n-side interconnection layer provided both inside the second opening and on the first insulating film, and an n-side metal pillar provided on the n-side interconnection layer, the n-side metal pillar being thicker than the n-side interconnection layer. 
 
     
     
       16. The device according to  claim 14 , wherein the second insulating film covers a periphery of the p-side metal pillar and a periphery of the n-side metal pillar.